Project description:In order to reveal so far unknown facets of the adaptation of B. subtilis to growth under high-salinity conditions, a whole-transcriptome analysis of B. subtilis BSB (168 Trp+) was performed using strand-specific tiling arrays (tiling step of 22 nucleotides). In addition, the effects of glycine betaine (GB) were analyzed under high salinity and standard growth conditions in a chemically defined medium. Important novel findings were a sustained low-level induction of the SigB-dependent general stress response and strong repression of biofilm matrix genes under high-salinity conditions. GB influences gene expression not only under high-salinity, but also under standard growth conditions without additional salt.
Project description:Sea cucumber, Apostichopus japonicus is a very important species for aquaculture, and its behavior and physiology can respond to the initial change in salinity. It is important to understand the molecular responses of A. japonicus when exposed to ambient changes in salinity In this study, RNA-seq provided a general overview of the gene expression profiles of the intestine of A. japonicus exposed to high salinity (SD40), normal salinity (SD30) and low salinity (SD20) environment.
Project description:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses”, “modulation of respiratory chain and related components”, and “ion homeostasis”. A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity respectively, and repressed by temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of temperature. Low salinity induced genes involved in “protein-folding-stress response”, suggesting disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by temperature. However, salt-induced cell motility was reduced at high temperature, possibly caused by an alteration of Na+ permeability by temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. In addition, compared to low salinity external iron increased hydroxyectoine accumulation by 20% at high salinity, but reduced the intracellular content of ectoines by 50% at high salinity plus high temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens
Project description:Algae of the genus Dunaliella are known to be able to grow in a wide range of salinities. To investigate which genes may be important for growth under extremely low or high salinities, a survey of the Dunaliella sp. transcriptome was performed by microarray analysis. For the cDNA microarray 778 expressed sequence tags (ESTs) were generated from a cDNA library of Dunaliella sp. The cDNA microarray was used to compare the transcription profile of cells that were acclimated to extreme saline conditions (0.08 M and 4.5 M NaCl) with the transcription profile of cells acclimated to an intermediate salinity at 1.5 M NaCl. The comparative microarray analysis indicated that 211 out of the 778 ESTs differed in their expression levels more than two-fold in cells grown at extreme different salinity when compared to cells grown at intermediate salinity (1.5M NaCl). The sequences of these 211 cDNAs were classified into 169 non-redundant gene clusters. Of these genes, the expression of 36 genes was increased and 69 genes were suppressed in cells grown at low salinity. The expression of 49 genes was increased and 85 genes were suppressed in cells grown at high salinity. One-hundred thirty four genes have been revealed to show up- and down-regulation by high salinity (4.5M NaCl). Of the high salinity-regulated genes 52% were also influenced by low salinity (0.08M NaCl), revealing a dense overlap between low and high salt responses. Only 35 genes are regulated independently by low salt condition. Strong relationships, however, were observed in the expression of these extreme salinity-responsive genes based on Venn diagram analysis, which found 70 genes that responded to these two salinity conditions. Refined expression analysis using gene-specific primers and real-time PCR for selected transcripts was in agreement with microarray results for most genes tested. This study provides the first large-scale survey of the transcriptome in the microalga Dunaliella sp. and it provides a platform for further functional investigation of differentially expressed genes in Dunaliella. Keywords: Low salt(0.08M NaCl) or high salt(4.5M NaCl)-acclimated cells
Project description:In order to understand the molecular mechanisms of salinity adaptation, high-throughput RNA-Seq was utilized to discover the gene expression profiles and pathways that responded to elevated salinity in the liver of T. s. elegans
Project description:Three rice major tissues, namely flag leaf, shoot and panicle, were involved in this study. Each tissue had two kinds stress treatment, drought and high salinity, in 3 different time courses. For drought treated samples, an additional water recovery was applied. Each experiment had three replicates. Keywords: Comparison of gene expression in three tissues with stress treatment and without treatment To globally elucidate potential genes involved in drought and high-salinity stresses responses in rice, an oligomer microarray covering 37,132 genes including cDNA or EST supported and putative genes was applied to study the expression profiling of shoot, flag leaf, and panicle under drought or high-salinity treatment. Three rice major tissues, namely flag leaf, shoot and panicle, were involved in this study. Each tissue had two kinds stress treatment, drought and high salinity, in 3 different time courses. For drought treated samples, an additional water recovery was applied. Each experiment had three replicates.
Project description:Salinity is a major factor that can affect greatly the viability of the fish larvae during their developing stages. Natural populations are exposed to high fluctuation in the environmental conditions. Also, salinity management is of high relevance in hatcheries. The objective of this study was to determine the biological effects of environmental salinities on larval development in sole. Larvae were exposed to two salinities, 10 and 36 ppt, from eggs until the 3 days after hatching. Expression profiles were determined using RNA-seq, microarray and validated using qPCR. Important malformations were identified. The identification of key molecular pathways affected by salinity can help to understand the effects of salinity during early developmental stages with a profound impact to evaluate the effects of climate change and improve hatchery practices.
Project description:Salinity is one of the significant factors that affect growth and cellular metabolism, including photosynthesis and lipid accumulation, in microalgae and higher plants. Microchloropsis gaditana CCMP526 can acclimatize to different salinity levels by accumulating compatible solutes, carbohydrates, and lipid as an energy storage molecule. We used proteomics to understand the molecular basis for acclimation of M. gaditana to increased salinity levels (55 and 100 PSU). Correspondence analysis (CA) was used for identification of salinity-responsive proteins (SRPs). The highest number of altered proteins was observed in 100 PSU. Gene Ontology (GO) enrichment analysis revealed a separate path of acclimation for cells exposed to 55 and 100 PSU. Osmolyte and lipid biosynthesis was up-regulated in high saline conditions. However, concomitantly lipid oxidation pathways were also up-regulated at high saline conditions, providing acetyl-CoA for energy metabolism through the TCA cycle. Carbon fixation and photosynthesis were tightly regulated, while chlorophyll biosynthesis was affected under high salinity conditions. Importantly, temporal proteome analysis of salinity-challenged M. gaditana revealed vital salinity-responsive proteins which could be used for strain engineering for improved salinity resistance.